Expansible cover



Aug. 13, 1940.

INVENTOR.

1' C. PrERcE' ,@mh M ATTORNEYS.

ug. 13,1940. R. c. PIERCE EXPANSIBLE COVER FilAed April 13, 1959 2 Sheets-Sheet 2 R. m is E n WI A PM 0.. E w R BY t EXPANSBLE COVER Robert C. Pierce, Niles,

Mich., assigner to National Standard Company, Niles, Mich., a corporation of Michigan Application April 13, 1939, Serial No. 267,636

2 Claims.

This invention relates to expansible wire covers, and is illustrated as embodied in a cover for a rubber tube or bag adapted to be expanded by oil under pressure to break down coal from a seam in a mine, the whole assembly being usually referred to as a mining cartridge.

An object of the invention is to increase the strength and durability of such covers by making them of special wire strands arranged in sets l0 carried over and under each other to form a tubular expansible braid.

Various features of novelty relate to the structure and arrangement of the strands to give the necessary strength to the tubular braid, and

still to shift readily on each other to facilitate the expansion and accompanying shortening of the cartridge;"1and its contraction and accompanying elongation.

The above and other objects and features of the invention will be apparentl from the following description of the illustrative' embodiment shown in the accompanying drawings, in which:

Figure 1 is an elevational view of one of my novel cartridges with a portion cut away to show the inner tube;

Figure 2 is an elevational view of the cartridge of Figure 1 expanded by oil pressure;

Figure 4'3 is a sectional view, greatly enlarged4 of the special wire strand used to make my novel cartridge; and

Figure 4 is a substantially full size view of one end of the cartridge in the expanded condition showing in detail the inter-relationship of the strands.

i The invention is lillustrated in the drawings and described below, as embodied in a coalmining expansible and contractible cartridge of the type described in my Patent No. 2,041,950,

to the cover of such a cartridge.

In the form shown, the cartridge includes an inner tube or bag I 0 of rubber, adapted to be expanded by hydraulic pressure which may run up to 2500 lbs. per square inch and which is protected by an expansible and contractible metallic cover comprising a novel tubular wire braid structure I2 having end ttings I4 and I6 secured thereto.

The tubular braid I2 is made up by carrying alternately over and under each other diagonally around the braid sets of wire strands I8, there being preferably three strands in each set, and each of the sets preferably extending alternately over and under three of the other sets.

Each of the strands I8, in order to secure maximum strength, is made up of wires of three sizes arranged as shown in Figure 3. The central wire 20 is of an intermediate size (e. g. .023 inch) and is surrounded in an intermediate layer by'six y. other wires 22 of substantially the same size.

important that the wires of the strands extend- 10 ing around the braid to the right should be wound to the left in their strands A(see Figure 4 at numeral 28) and the wires of the strands extending around the braid to the left should be wound to the right (see Figure 4 at numeral 30) so that 15 the strands allA tighten asthe pressure is applied inside the cartridge.

It will be seen that in the completed cartridge. when the pressure -is applied internally, all of the strands I8 tend to tighten rather than to 20 loosen.

While one illustrative embodiment has been described in detail, it is not my intention to limit the scope of the invention to that particular embodiment, or otherwise than by the terms of 25 l the appended claims.

I claim: Y

1. An expansible cover, suitable for reinforcing. articles such as mining cartridges and the like, comprising sets of strands carried over` and under each other to form a tubular expansible braid and having fend iittiings to which the ends of the braid are secured, the sets of strands extending alternately to the right and to the left about the braid, the strands of each set which 35.

extends to the right being made u p of wires Wound with a left-hand pitch and the strands of each set which extends to the left being made up of wires wound with a right-hand pitch so that all oi the strands tend to tighten as the 40 cover is expanded. l

2. An expansible cover, suitable for reinforcing articles such as mining cartridges and the like, comprising sets of strands each of which sets consists of at least three-strands and each of strands extending alternately to the right and to the leftabout the braid, the strands of each set which extends to the right being made up of wires wound with a left-hand pitch and the strands'of -each vset which extends to the left being made up of wires wound with a right-'hand 65 pitch vso that all of the strands tend to tighten as the cover is expanded.

ROBERT C. PIERCE. 

